Female in military squad is not suitable (5)
I believe the answer is:
unfit
'not suitable' is the definition.
(I've seen this before)
'female in military squad' is the wordplay.
'female' becomes 'f' (abbreviation).
'in' is an insertion indicator.
'military squad' becomes 'unit' (I've seen this in another clue).
'f' going inside 'unit' is 'UNFIT'.
'is' is the link.
(Other definitions for unfit that I've seen before include "Ill-equipped" , "Incompetent" , "Not healthy" , "Not in good shape physically" , "Unsuitable" .)